Electric switch



April 29, 1947. H. CARLING ELECTRIC SWITCH 2 Sheets-Sheet 1 Filed Oct. '7, 1945 Inventor: He Z/ge Hurling a m w w fi m April 29, 1947. H. cARuNc;

ELECTRIC SWITCH Filed Oct. 7, 1945 2 Shgets-Sheet 2 r r Z 1 we M m Patented Apr. 29, 1947 ELECTRIC SWITCH Helge Carling, West Hartford, Conn., assignor to The Carling Tool & Machine Company, Hartford, Conn, a corporation of Connecticut Application October 7, 1943, Serial No. 505,293

1 Claim.

This invention relates to electric snap switches. More particularly it relates to electric snap switches of the type in which the movable contact member is capable of occupying a neutral position and two other positions in which respective circults are closed. The object of the invention is the provision of a. durable and reliable switch mechanism comprising few and conveniently formed parts combined in an arrangement that is simple to assemble.

In the drawings, Figure 1 is a plan view of a three-pole switch constructed in accordance with my invention. Figure 2 is a side view of the switch shown in Fig. 1. Figure 3 is a sectional view on line 3-3 of Fig. 1. Figure 4 is a detail view partly in section of a switch operating lever. Figure 5 is a view similar to Fig. 3 but with switch operating lever in a different position. Figure 6 is a top view of switch with cover plates removed. Figure 7 is a transverse sectional view on line l'l of Fig. 2. Figure 8 is a sectional view on line 88 of Fig. 1. Figure 9 includes three detail views of a contact member. and Figure 10 is a detail view of another contact member.

Referring to the drawings, the switch includes a base or casing l formed of suitable insulating material such as Bakelite. To receive certain parts of the switch mechanism, case I is recessed from one side to form the substantially rectangular cavity 2, from the four corners of which identically formed channels 3, 4, 5 and 6 extend to receive and definitely locate stationary metal parts hereinafter fully described. Side walls 8 and 9 of cavity 2 are provided with slight depressions ill and l I which serve a. purpose that will hereinafter appear. Through solid portions of base I adjacent each end thereof, respective holes l2 and I3 are formed to receive screws I 4 and I5 respectively which secure to the case a metal cover member l6 formed to extend over cavity 2 and provided with side flanges I! which straddle the case and overlie the side wall 8 and 9 thereof. A lining l8 of insulating material and of a shape similar to cover It is interposed between the latter and the base to complete a suitable housing for the switch mechanism. To provide a well known means of mounting the switch upon a plate or other support (not shown) cover l6 has secured thereto a bushing I9, externally threaded to receive holding nuts and 2L Bushing I 9 also serves as a support for a pivot pin 22 on which is mounted a lever 23 comprising both the switch manipulating handle 24 and support for contact 25, the latter being insulated from the lever by bushing 26 and collar 21 which are riveted to the hollow extension 28 of said lever, see Fig. 4.

For a purpose that will presently appear one side of contact is provided with a, notch 30 having inclined sides which respectively merge into lobes 32 and 33.

Referring to Figs. 3 and 5 it will be apparent that switch lever 23 is operable about its pivot 22 to carry contact 25 in an arcuate path extendin lengthwise of cavity 2. On one side of this path and located to be engaged by movable contact 25 are three terminal contacts. The intermediate contact 49. preferably made from a flat strip of spring metal, is formed into U-shape with one branch 4| longer than the other 42. The long or outer branch 4| is provided with eyelet 43 to which a wire may be conveniently attached. Assembled with the case I, contact straddles side wall 8 with the transverse portion of the U seated in locating depression Ill, before described. The part 40 is held in the position indicated by the overlying cover l6, flanges ill and lining it which hold branch 4| against the outside of side Wall 8 with the inner branch 42 spaced from the inside surface of side wall 8. Such spacing of branch 42 from the inner wall of the casing is provided to permit flexing of the branch in movement transverse to the path of movement of the bridging contact 25. This transverse movement of branch 42 is effected in one direction by its inherent resiliency and in the opposite direction by such movement of contact 25 as is effected by manipulation of handle 24. To provide for the latter action the free extremity of resilient branch 42 ispressed into V-form thereby producing a point 44 suitable to serve like a cam follower to engage contact 25. This point 44 is flanked by respective inclined surfaces 45 and 46 so that whenv contact 25 is moved by its lever 24 either lobe 32 or 33 forces point 44 laterally outward thereby increasing the pressure with which said point 44 bears against contact 25. As either lobe 32 or 33 is passed over point 44 as by manipulation of lever 24, it will pass onto either inclined surface 45 or 46 and contact 25 will be impelled by the resiliency of branch 42 to complete its movement with a snap action. From the foregoing explanation it follows that when switch lever 23 is moved in one direction from its intermediate position, lobe 32 of contact 25 forces branch 42 laterally outward until said lobe 32 engages inclined surface 45. Then the tension of branch 42 is effective to continue movement of contact 25 with snap action to one extremity of its range of movement and into engagement with the contact 50 thereby closing the circuit between indicated terminals 40 and 50. Similarly when switch lever 23 is moved in the opposite direction from its intermediate position, lobe 33 of contact 25 acts on branch 42 until it eventually snapssaid contact to the opposite extremity of its range of movement to close circuit between terminals 40 and 60.

Contact 50 like contact 40 preferably is made from a flat strip of spring metal so formed that it is engaged by its receiving channel in a manner to insure fixed position of the part without use of holding means other than the overlying cover elements l6 and I8. That is to say the contact 50 is of a height substantially equal to that of channel 3, laterally it is made to engage sides of the channel by providing the reverse bend I, and one edge of the contact is indented as at 52 to interlock with similar contour of the adjacent wall of said channel. The reverse bend 51 provides also for slight flexing of the inner end of contact 59, said end presenting an inclined surface 54 for desirable engagement with lobe 33 of movable contact as when the latter is in position to close the circuit between the terminal contacts and 50. The outer end of contact 59 extends outside casing I and is provided with an eyelet 55 for convenient attachment of a wire thereto. To impart greater stifiness to the shank of contact between eyelet and reverse bend 5i it may be indented as at 53. From the foregoing description of contact 25 in its circuit closing position between contacts 40 and 50 it will be clearly understood that at the other end of its arc of movement contact 25 may serve to close a similar circuit including terminal contact 48 and another contact as 65. The latter is of the opposite hand in formation to contact 5B, but otherwise it is identical therewith.

It has been explained that when surface 45 of contact 40 is engaged by lobe 32 of contact 25 K the latter will be moved with a snap action in one direction and when surface 45 is engaged by lobe 33 contact 25 will be similarly moved in the opposite direction. In one of the extreme positions indicated contact 25 closes one circuit and in the other of said positions contact 25 closes the other circuit. From either of these positions contact 25 may be moved toward a central or neutral position by manipulation of switch handle 24 until point 44 of contact 48 passes into the V-notch formed by lobes 32 and 33, then the final movement of contact 25 to neutral position is completed With a snap action under influence of stored up tension in terminal contact 40.

Contacts 40, 59 and 50 have been described as located on one side of the path of movement of contact 25. On the opposite side of this path are located members 49, 59 and 69. As illustrated in the drawings the purpose of members 49, 53

and 69 is to counterbalance lateral thrust of members 40, 50 and on contact 25. Thus member 49 is similar in every respect to contact 43 except that its outer branch is shorter and is not provided with an eyelet. It is mounted on wall 9, of the casing and held in place in depression I! of said wall by the overlying lining l3 and cover plate ll. Likewise members 59 and 69 and their support in respective channels 5 and 6 correspond to the described shape and mounting of contacts 50 and 6D the only difference being in the omission from members 59 and 60 of wire receiving eyelets. It will be understood however that members 50 and 59 might serve as one pair of terminals and members 60 and 69 as another pair, in this case both members 40 and 49 would be nonterminals but would serve with snap action to move contact 25 to circuit closing end positions from a neutral intermediate position and from the end positions to the intermediate position.

Attention is particularly directed to the fact that resilient extremities of side wall contacts 40 and 49 respectively engage the bridging contact 25 on opposed sides thereof, thereby equalizing the divided pressure applied to the latter for actuating it and presenting the essential mechanism in a balanced arrangement that is conducive to its smooth operation and consequent long wear of the bearing surfaces of its moving parts. Furthermore by placing spring elements 40 and 49 of the fiat type at the sides of the movable bridging contact 25 the resulting mechanism, in assembly, is of a compact arrangement suitable for installment in spaces of limited depth.

The foregoing description sets forth one convenient form of embodiment of my invention but various modifications in specific detail may be made without departure from the spirit and scope of the invention as defined by the appended claim.

Having thus described my invention, what I claim is:

An electric snap switch, including in combination, an insulating casing, a cover secured to the casing, a bushing secured to the cover, a lever supported by the bushing, a contact carried by the lever and operable thereby to be moved in a predetermined path within the casing, said contact having oppositely disposed notches, stationary contact elements mounted on the side walls of the casing and presenting within the casing resilient extremities adapted to engage respective notches in the movable contact when the latter is in an intermediate position, a pair of contacts carried by the casing at each end thereof, the members of each pair forming within the casing a gap adapted to be bridged by the movable contact when it is moved to respective ends of its range of movement by snap action effected by the side wall contacts.

HELGE CARLING.

REFERENCES CITED r'ne following references are of record in the file of this patent:

UNITED STATES PATENTS 

